Today IPv6 over IPv4 are widely used to connect large regional IPv6 networks. Many users of the internet have portable computers and want to stay connected to the internet when they visit a distant internet site and even on the road in between. IPv6 is the next generation Internet protocol designed as a successor to the IP version 4. IPv6 was designed to enabled high-performance, scalable Internet. This was achieved by overcoming many of weakness of IPv4 protocol and by adding several new features. This paper demonstrates the IP version and shows when to immigrate from IPv4 to IPv6.